Dare mutants behave abnormally in response to olfactory repellents and have defects in male courtship behavior. The long-term goal of this project is to characterize the role of dare in the function and development of the Drosophila olfactory system. Dare encodes the Drosophila homologue of adrenodoxin reductase (AR), which has been shown in mammals to be essential for the key, rate limiting step in the synthesis of all steroid hormones. Dare is the first mutant with a lesion in the steroid biosynthetic pathway and links steroid hormones with sensory behavior. Several new dare alleles will be tested in a variety of behavioral and electrophysiological olfactory paradigms. Nervous system morphology in dare mutant animals will be observed at several developmental stages in an attempt to identify the nature, timing, and extent of any abnormalities. I will attempt to rescue behavioral and developmental defects using a transformant line harboring a heat shock-inducible AR cDNA construct (hs-AR). In the absence of full phenotypic rescue by hs-AR, I will generate flies harboring a genomic fragment which covers the AR gene for similar experiments and begin a screen for new dare alleles. After dare has been rigorously identified as AR, developmental Northern analysis and in situ hybridizations to RNA in tissue sections will be used to determine the pattern and developmental time course of dare expression. Time permitting, I will screen for a temperature-sensitive allele of dare and attempt to rescue male courtship defects by the directed expression of dare in male pheromone-producing tissues.